The suboccipital triangle is a muscular triangle situated on each side of the midline in the back. It is bounded superiorly by the rectus capitis posterior major and obliquus capitis superior muscles, inferiorly by the obliquus capitis inferior, and has the semispinalis capitis, splenius capitis, and longissimus capitis muscles forming its roof. The third part of the vertebral artery, the first cervical nerve, and suboccipital plexus of veins pass through the suboccipital triangle. A cisternal puncture procedure approaches the cisterna magna through the foramen magnum by piercing the posterior atlanto-occipital

1. Suboccipital triangle

2. • Pair of muscular triangles
• Situated each side of the midline

3. • Muscles of back are arranged in 4
layers
• I layer
• Trapezius
• Latissimus dorsi
• II layer
• Levator Scapulae
• Rhomboideus minor
• Rhomboideus major
• III layer
• Erector spinae
• 3 groups
• Lateral
• Iliocostalis
• Intermediate
• Longissimus
• Medial
• Semispinalis
• IV layer
• Rotators, interspinalis, intertransverses &
muscles forming the suboccipital triangle

4. Suboccipital triangle
 Roof
• Semispinalis capitis (Medially)
• Splenius capitis & longissimus
capitis (Laterally)
• Floor
• Posterior arch of atlas
• Posterior atlanto-occipital membrane
Semispinalis capitis
Splenius capitis
Longissimus
capitis

5. Suboccipital triangle
Boundaries
• Supero-medially
• Rectus capitis posterior major
• Supero-laterally
• Obliquus capitis superior
• Inferiorly
• Obliquus capitis inferior

6. Suboccipital triangle - contents
• Third part of vertebral artery
• First cervical nerve (suboccipital
nerve)
• Suboccipital plexus of veins

8. Applied anatomy
• Cisternal puncture
• Procedure to approach cisterna
magna
• In posterior cranial fossa through
foramen magnum
• By piercing the posterior atlanto-
occipital membrane
• To obtain CSF